From 966478cac48fed23e3a26e40f3298a1585ffac72 Mon Sep 17 00:00:00 2001
From: Brian Gough <brian.gough@overleaf.com>
Date: Tue, 11 Jun 2019 14:11:46 +0100
Subject: [PATCH 1/2] fix hash check to use 'v' field instead of version

---
 .../document-updater/app/coffee/ShareJsUpdateManager.coffee     | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/services/document-updater/app/coffee/ShareJsUpdateManager.coffee b/services/document-updater/app/coffee/ShareJsUpdateManager.coffee
index 66b8367395..c81cccdc77 100644
--- a/services/document-updater/app/coffee/ShareJsUpdateManager.coffee
+++ b/services/document-updater/app/coffee/ShareJsUpdateManager.coffee
@@ -26,7 +26,7 @@ module.exports = ShareJsUpdateManager =
 		logger.log project_id: project_id, doc_id: doc_id, update: update, "applying sharejs updates"
 		jobs = []
 		# record the update version before it is modified
-		incomingUpdateVersion = update.version
+		incomingUpdateVersion = update.v
 		# We could use a global model for all docs, but we're hitting issues with the
 		# internal state of ShareJS not being accessible for clearing caches, and
 		# getting stuck due to queued callbacks (line 260 of sharejs/server/model.coffee)

From 984b2d38e6b0867fe4dc7dc2f17f4e41277b34cd Mon Sep 17 00:00:00 2001
From: Brian Gough <brian.gough@overleaf.com>
Date: Tue, 11 Jun 2019 16:33:14 +0100
Subject: [PATCH 2/2] add unit tests

---
 .../ShareJsUpdateManagerTests.coffee            | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/services/document-updater/test/unit/coffee/ShareJsUpdateManager/ShareJsUpdateManagerTests.coffee b/services/document-updater/test/unit/coffee/ShareJsUpdateManager/ShareJsUpdateManagerTests.coffee
index 236112684a..363705845f 100644
--- a/services/document-updater/test/unit/coffee/ShareJsUpdateManager/ShareJsUpdateManagerTests.coffee
+++ b/services/document-updater/test/unit/coffee/ShareJsUpdateManager/ShareJsUpdateManagerTests.coffee
@@ -3,6 +3,7 @@ chai = require('chai')
 should = chai.should()
 modulePath = "../../../../app/js/ShareJsUpdateManager.js"
 SandboxedModule = require('sandboxed-module')
+crypto = require('crypto')
 
 describe "ShareJsUpdateManager", ->
 	beforeEach ->
@@ -26,8 +27,10 @@ describe "ShareJsUpdateManager", ->
 		beforeEach ->
 			@lines = ["one", "two"]
 			@version = 34
-			@update = {p: 4, t: "foo"}
 			@updatedDocLines = ["onefoo", "two"]
+			content = @updatedDocLines.join("\n")
+			@hash = crypto.createHash('sha1').update("blob " + content.length + "\x00").update(content, 'utf8').digest('hex')
+			@update = {p: 4, t: "foo", v:@version, hash:@hash}
 			@model =
 				applyOp: sinon.stub().callsArg(2)
 				getSnapshot: sinon.stub()
@@ -90,6 +93,18 @@ describe "ShareJsUpdateManager", ->
 			it "should call the callback with the error", ->
 				@callback.calledWith(@error).should.equal true
 
+		describe "with an invalid hash", ->
+			beforeEach (done) ->
+				@error = new Error("invalid hash")
+				@model.getSnapshot.callsArgWith(1, null, {snapshot: "unexpected content", v: @version})
+				@model.db.appliedOps["#{@project_id}:#{@doc_id}"] = @appliedOps = ["mock-ops"]
+				@ShareJsUpdateManager.applyUpdate @project_id, @doc_id, @update, @lines, @version, (err, docLines, version, appliedOps) =>
+					@callback(err, docLines, version, appliedOps)
+					done()
+
+			it "should call the callback with the error", ->
+				@callback.calledWith(@error).should.equal true
+
 	describe "_listenForOps", ->
 		beforeEach ->
 			@model = on: (event, callback) =>